Problem # $4[7$ Marks$]$:

For given expression of the signal

$y(t)={\displaystyle \underset{n=1}{\overset{}{}}}\frac{4C(1-cosn)}{(n{)}^2}cos(\frac{2nt}{T})$

Determine the value of $A_n$ if $n$ even and if $n$ is odd?

$\frac{1}{2}$

$q,$

$q,$

$q,$

Determine the first three nonzero terms of this fourier series? $$

$12$

$1q,$

$q,$

$q,$

$q,$

$q,$

$3.$ Draw the frequency spectrum of $y(t)$